Option Outstanding Currently Exercisable By Exercise Price (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
$ 0.42 - $ 1.19
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 0.42
Range of Exercise Prices, Upper Limit	$ 1.19
Number of option outstanding	1,345
Weighted average remaining contractual life (in years)	2 years 9 months 26 days
Options Outstanding, weighted average exercise price	$ 1.03
Options exercisable, weighted-average exercise price	$ 1.00
Options exercisable Number of Exercisable	986
$ 1.21- $ 1.23
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 1.21
Range of Exercise Prices, Upper Limit	$ 1.23
Number of option outstanding	1,110
Weighted average remaining contractual life (in years)	3 years 11 days
Options Outstanding, weighted average exercise price	$ 1.22
Options exercisable, weighted-average exercise price	$ 1.22
Options exercisable Number of Exercisable	764
$ 1.30 - $ 2.03
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 1.30
Range of Exercise Prices, Upper Limit	$ 2.03
Number of option outstanding	1,302
Weighted average remaining contractual life (in years)	3 years 7 months 28 days
Options Outstanding, weighted average exercise price	$ 1.67
Options exercisable, weighted-average exercise price	$ 1.66
Options exercisable Number of Exercisable	691
$ 2.16 - $ 2.83
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 2.16
Range of Exercise Prices, Upper Limit	$ 2.83
Number of option outstanding	380
Weighted average remaining contractual life (in years)	5 years 8 months 16 days
Options Outstanding, weighted average exercise price	$ 2.30
Options exercisable, weighted-average exercise price	$ 2.45
Options exercisable Number of Exercisable	18
$ 2.90 - $ 2.90
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 2.90
Range of Exercise Prices, Upper Limit	$ 2.90
Number of option outstanding	1,273
Weighted average remaining contractual life (in years)	4 years 9 months 11 days
Options Outstanding, weighted average exercise price	$ 2.90
Options exercisable, weighted-average exercise price	$ 2.90
Options exercisable Number of Exercisable	376
$ 2.98 - $ 3.29
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 2.98
Range of Exercise Prices, Upper Limit	$ 3.29
Number of option outstanding	1,130
Weighted average remaining contractual life (in years)	5 years 8 months 9 days
Options Outstanding, weighted average exercise price	$ 3.28
Options exercisable, weighted-average exercise price	$ 3.17
Options exercisable Number of Exercisable	31
$ 3.39 - $ 3.78
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 3.39
Range of Exercise Prices, Upper Limit	$ 3.78
Number of option outstanding	1,098
Weighted average remaining contractual life (in years)	4 years 18 days
Options Outstanding, weighted average exercise price	$ 3.72
Options exercisable, weighted-average exercise price	$ 3.71
Options exercisable Number of Exercisable	497
$ 3.88 - $ 4.30
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 3.88
Range of Exercise Prices, Upper Limit	$ 4.30
Number of option outstanding	1,209
Weighted average remaining contractual life (in years)	4 years 11 months 12 days
Options Outstanding, weighted average exercise price	$ 4.25
Options exercisable, weighted-average exercise price	$ 4.06
Options exercisable Number of Exercisable	132
$ 4.35 - $ 4.66
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 4.35
Range of Exercise Prices, Upper Limit	$ 4.66
Number of option outstanding	1,123
Weighted average remaining contractual life (in years)	4 years 4 months 28 days
Options Outstanding, weighted average exercise price	$ 4.53
Options exercisable, weighted-average exercise price	$ 4.52
Options exercisable Number of Exercisable	465
$ 4.72 - $ 11.88
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 4.72
Range of Exercise Prices, Upper Limit	$ 11.88
Number of option outstanding	951
Weighted average remaining contractual life (in years)	3 years 8 months 23 days
Options Outstanding, weighted average exercise price	$ 6.33
Options exercisable, weighted-average exercise price	$ 6.67
Options exercisable Number of Exercisable	745
$ 0.42 - $ 11.88
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 0.42
Range of Exercise Prices, Upper Limit	$ 11.88
Number of option outstanding	10,921
Weighted average remaining contractual life (in years)	4 years 2 months 1 day
Options Outstanding, weighted average exercise price	$ 3.07
Options exercisable, weighted-average exercise price	$ 2.92
Options exercisable Number of Exercisable	4,705